Hook fastener



FIG. 1 is a front perspective view of a hook fastener showing my new design;

FIG. 2 is a rear perspective view thereof;

FIG. 3 is a left-side elevational view thereof;

FIG. 4 is a right-side elevational view thereof;

FIG. 5 is a front elevational view thereof;

FIG. 6 is a rear elevational view thereof;

FIG. 7 is a top plan view thereof; and,

FIG. 8 is a bottom plan view thereof. 

CLAIM The ornamental design for a hook fastener, as shown and described. 